Elevated tumor mutation burden and immunogenic activity in patients with hormone receptor-negative or human epidermal growth factor receptor 2-positive breast cancer

Molecular profiling of male breast cancer by multigene panel testing: Implications for precision oncology

Introduction

Compared with breast cancer (BC) in women, BC in men is a rare disease with genetic and molecular peculiarities. Therapeutic approaches for male BC (MBC) are currently extrapolated from the clinical management of female BC, although the disease does not exactly overlap in males and females. Data on specific molecular biomarkers in MBC are lacking, cutting out male patients from more appropriate therapeutic strategies. Growing evidence indicates that Next Generation Sequencing (NGS) multigene panel testing can be used for the detection of predictive molecular biomarkers, including Tumor Mutational Burden (TMB) and Microsatellite Instability (MSI).

Methods

In this study, NGS multigene gene panel sequencing, targeting 1.94 Mb of the genome at 523 cancer-relevant genes (TruSight Oncology 500, Illumina), was used to identify and characterize somatic variants, Copy Number Variations (CNVs), TMB and MSI, in 15 Formalin-Fixed Paraffin-Embedded (FFPE) male breast cancer samples.

Results and discussion

A total of 40 pathogenic variants were detected in 24 genes. All MBC cases harbored at least one pathogenic variant. PIK3CA was the most frequently mutated gene, with six (40.0%) MBCs harboring targetable PIK3CA alterations. CNVs analysis showed copy number gains in 22 genes. No copy number losses were found. Specifically, 13 (86.7%) MBCs showed gene copy number gains. MYC was the most frequently amplified gene with eight (53.3%) MBCs showing a median fold-changes value of 1.9 (range 1.8-3.8). A median TMB value of 4.3 (range 0.8-12.3) mut/Mb was observed, with two (13%) MBCs showing high-TMB. The median percentage of MSI was 2.4% (range 0-17.6%), with two (13%) MBCs showing high-MSI. Overall, these results indicate that NGS multigene panel sequencing can provide a comprehensive molecular tumor profiling in MBC. The identification of targetable molecular alterations in more than 70% of MBCs suggests that the NGS approach may allow for the selection of MBC patients eligible for precision/targeted therapy.

Immunotherapy and immunobiomarker in breast cancer: current practice and future perspectives

Among the new cancer cases and resulting deaths among women worldwide, breast cancer is the most significant threat to women's health. In recent years, immunotherapy was initially used to treat patients with metastatic breast cancer, where it demonstrated its unique value by providing a novel way to improve therapeutic effects and prolong survival time. With the development of clinical trials related to immunotherapy for breast cancer, tumour vaccines, such as DNA vaccines, have been observed to improve the disease-free survival (DFS) and overall survival (OS) of patients. Monoclonal antibodies have also shown good efficacy, and adoptive cell therapies, such as CAR-T, exhibit strong tumour killing ability and good safety, and thus, these therapies may comprise a new strategy for the treatment of breast cancer. These breakthrough successes have promoted the achievement of "individualized" breast cancer treatment. Moreover, a recent study showed that patients with various cancer types with a higher tumour mutational burden (TMB) are more likely to benefit from immunotherapy. As research progresses, TMB may also demonstrate a certain clinical significance in the treatment of breast cancer. This paper reviews the latest research progress on breast cancer immunotherapy and the predictive value and application status of TMB in immunotherapy regimens for breast cancer patients to provide a reference for further in-depth studies of breast cancer immunotherapy.

Immunological Landscape of HER-2 Positive Breast Cancer

Understanding the biological aspects of immune response in HER2+ breast cancer is crucial to implementing new treatment strategies in these patients. It is well known that anti-HER2 therapy has improved survival in this population, yet a substantial percentage may relapse, creating a need within the scientific community to uncover resistance mechanisms and determine how to overcome them. This systematic review indicates the immunological mechanisms through which trastuzumab and other agents target cancer cells, also outlining the main trials studying immune checkpoint blockade. Finally, we report on anti-HER2 vaccines and include a figure exemplifying their mechanisms of action.

Breast Cancer Heterogeneity

Breast tumor heterogeneity is a major challenge in the clinical management of breast cancer patients. Both inter-tumor and intra-tumor heterogeneity imply that each breast cancer (BC) could have different prognosis and would benefit from specific therapy. Breast cancer is a dynamic entity, changing during tumor progression and metastatization and this poses fundamental issues to the feasibility of a personalized medicine approach. The most effective therapeutic strategy for patients with recurrent disease should be assessed evaluating biopsies obtained from metastatic sites. Furthermore, the tumor progression and the treatment response should be strictly followed and radiogenomics and liquid biopsy might be valuable tools to assess BC heterogeneity in a non-invasive way.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immunotherapy for the treatment of breast cancer

Breast cancer has historically been a disease for which immunotherapy was largely unavailable. Recently, the use of immune checkpoint inhibitors (ICIs) in combination with chemotherapy for the treatment of advanced/metastatic triple-negative breast cancer (TNBC) has demonstrated efficacy, including longer progression-free survival and increased overall survival in subsets of patients. Based on clinical benefit in randomized trials, ICIs in combination with chemotherapy for the treatment of some patients with advanced/metastatic TNBC have been approved by the United States (US) Food and Drug Administration (FDA), expanding options for patients. Ongoing questions remain, however, about the optimal chemotherapy backbone for immunotherapy, appropriate biomarker-based selection of patients for treatment, the optimal strategy for immunotherapy treatment in earlier stage disease, and potential use in histological subtypes other than TNBC. To provide guidance to the oncology community on these and other important concerns, the Society for Immunotherapy of Cancer (SITC) convened a multidisciplinary panel of experts to develop a clinical practice guideline (CPG). The expert panel drew upon the published literature as well as their clinical experience to develop recommendations for healthcare professionals on these important aspects of immunotherapeutic treatment for breast cancer, including diagnostic testing, treatment planning, immune-related adverse events (irAEs), and patient quality of life (QOL) considerations. The evidence-based and consensus-based recommendations in this CPG are intended to give guidance to cancer care providers treating patients with breast cancer.

Improving Breast Cancer Responses to Immunotherapy-a Search for the Achilles Heel of the Tumor Microenvironment

PURPOSE OF REVIEW

To explore the role of the tumor microenvironment (TME) in breast cancer, identify the changes that occur in the TME during breast cancer progression, and explore the possibility of modifying the TME to improve immune checkpoint inhibitor responses.

RECENT FINDINGS

Emerging evidence shows the TME may be shaped by internal and external factors. Preclinical data suggests it may be possible to shift the TME to allow for better immune infiltration. In this review, we summarize emerging evidence of changes in the TME and how it can affect prognosis and responses to therapy. We also examine pre-clinical and clinical research aiming at modulating TME to increase proportion of patients who benefit from immune checkpoint inhibitors. The composition of the TME in breast cancer is likely dynamic and may be altered. These changes may lead to more or less responses to immunotherapy.

Stratification of Estrogen Receptor-Negative Breast Cancer Patients by Integrating the Somatic Mutations and Transcriptomic Data

Patients with estrogen receptor-negative breast cancer generally have a worse prognosis than estrogen receptor-positive patients. Nevertheless, a significant proportion of the estrogen receptor-negative cases have favorable outcomes. Identifying patients with a good prognosis, however, remains difficult, as recent studies are quite limited. The identification of molecular biomarkers is needed to better stratify patients. The significantly mutated genes may be potentially used as biomarkers to identify the subtype and to predict outcomes. To identify the biomarkers of receptor-negative breast cancer among the significantly mutated genes, we developed a workflow to screen significantly mutated genes associated with the estrogen receptor in breast cancer by a gene coexpression module. The similarity matrix was calculated with distance correlation to obtain gene modules through a weighted gene coexpression network analysis. The modules highly associated with the estrogen receptor, called important modules, were enriched for breast cancer-related pathways or disease. To screen significantly mutated genes, a new gene list was obtained through the overlap of the important module genes and the significantly mutated genes. The genes on this list can be used as biomarkers to predict survival of estrogen receptor-negative breast cancer patients. Furthermore, we selected six hub significantly mutated genes in the gene list which were also able to separate these patients. Our method provides a new and alternative method for integrating somatic gene mutations and expression data for patient stratification of estrogen receptor-negative breast cancers.

Upregulation of RAC3 in bladder cancer predicts adverse clinical outcome and increased tumor immune response

The relationship between RAC3 expression and clinical outcome in bladder cancer (BLCA) was uncertain. In this study, the expression level of RAC3 in BLCA and its clinical outcome were analyzed through various independent public databases. The mRNA expression level of RAC3 in BLCA and normal bladder was evaluated from the Gene Expression Omnibus (GEO), Oncomine, and The Cancer Genome Atlas (TCGA) database. The protein expression of RAC3 in BLCA and normal bladder was investigated from immunohistochemical images through the Human Protein Atlas (HPA) database. Next, gene tumor immune analyses were performed. Furthermore, gene set enrichment analysis (GESA) by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes enrichment (KEGG) for RAC3 and its co-expressed genes were performed. Then, GESA was also performed to validate the KEGG pathways by the different expression of RAC3 in BLCA. The results indicated that, compared with normal bladder, the mRNA and protein expression of RAC3 in BLCA were both significantly higher than those of normal bladder tissues (P<0.05). The tumor immune analyses indicated RAC3 was associated with microsatellite instability, tumor mutational burden, tumor immune microenvironment, and immune cell infiltration level evaluation (P<0.05). The survival analysis result demonstrated that upregulation of RAC3 was associated with adverse survival in BLCA (P<0.05). Taken together, these findings suggest that RAC3 may be associated with adverse clinical outcome and increased tumor immune response in BLCA, and may be a prognostic and immunotherapy marker for BLCA.